Ultrasonic energy is a powerful generator of biological effects. There are three primary benefits to ultrasound. The first is the speeding up of the healing process from an increase in blood flow in a treated area. The second is a decrease in pain from reduction of swelling and edema. The third is gentle massage of muscles tendons and/or ligaments in a treated area because no strain is added and any scar tissue is softened.
Therapeutic ultrasound provides two main effects: thermal and non-thermal. Thermal effects are due to the absorption of the sound waves. Non thermal effects are from cavitation, microstreaming and acoustic streaming. Cavitational effects result from the vibration of tissue causing microscopic bubbles to form, which transmit vibrations in a way that directly stimulates cell membranes. This physical stimulation appears to enhance the cell-repair effects of the inflammatory response. Therapeutic applications of ultrasonic heating utilize longer durations of heating with unfocused beams, or utilize higher intensity than diagnostic ultrasound. The use of unfocused heating, for example in physical therapy to treat highly absorbing tissues such as bone or tendon, can be moderated to produce enhanced healing without injury.
Ultrasound is applied using a transducer or hand probe that is in direct contact with the patient's skin. Gel is used on the surfaces of the head of the hand probe to reduce friction and assist transmission of the ultrasonic waves. Therapeutic ultrasound in physical therapy is alternating compression and rarefaction of sound waves with a frequency of >20,000 cycles/second. Therapeutic ultrasound frequency used is generally 0.7 to 3.3 MHz.
Maximum energy absorption in soft tissue occurs from 2 to 5 cm. Intensity decreases as the waves penetrate deeper.
Conditions for which ultrasound may be used for treatment include the following examples: ligament sprains, muscle strains, tendonitis, joint inflammation, plantar fasciitis, metatarsalgia, facet irritation, impingement syndrome, bursitis, rheumatoid arthritis, osteoarthritis, and scar tissue adhesion.
Study has shown that ultrasound helps in enhancing the metabolic activities of cells, thus helping in tissue repair, especially in soft tissue injuries.
U.S. Pat. No. 7,431,704 to Babaev et al. and titled Apparatus and Method for the Treatment of Tissue with Ultrasound Energy by Direct Contact, discloses an apparatus and method for the treatment of tissue, such as hard and soft tissues, wounds, tumors, muscles, and cartilage, through the direct contact of ultrasound energy. See Abstract. Ultrasound energy is delivered to a target area through direct contact with an ultrasound tip. Ultrasound energy is also delivered through direct contact with a coupling medium. The ultrasound tip is specially designed to comprise of a cavity area for controlled fragmentation and the simultaneous sonication of a target area. The specially designed ultrasound tip allows for ultrasound energy to focus on a target area. The ultrasound apparatus may be moved in a variety of different directions during the treatment of tissue.
U.S. Patent Appln. Publn. No. 20070299369 also to Babaev et al. and titled Ultrasound Wound Care Device and Method, discloses an ultrasound device and method for treating wounds. The ultrasound wound care device comprises a generator, an ultrasound transducer, an ultrasound horn, and a cavitation chamber. The device may further comprise a fluid, non-atomized, coupling medium. Ultrasound titled Low- and Mid-Frequency Ultrasound Device with Enhanced Cavitation Effect in Combination with Radial In-Depth Skin Therapy, discloses a device for treatment of subcutaneous fat cells, specifically to a device that uses low- and mid-frequency ultrasound waves in combination with radial deep skin therapy. A low- and mid-frequency focused ultrasound device for cavitation in combination with radial deep therapy that comprises a handle (1), a fastening ring (3), a bell-shaped housing (2), an ultrasound source and a vacuum pump, characterized in that low-frequency ultrasound cavitation therapy is performed simultaneously with vacuum therapy with a skin fold, and additionally characterized in that excess gel is removed via a filtration system in the handle.